Soybeans are under pressure, down 4.41% at $9.92 a bushel, after China fired back at US tariffs with proposed measures of its own.

Late Tuesday, China announced plans to impose tariffs on 106 US goods that have a combined trading value of more than $50 billion annually. The proposed measures include tariffs of 25% on soybeans, automobiles, and chemicals.

That news was followed by a swift sell-off in soybeans futures at the Chicago Board of Trade. May soybean futures tumbled more than 4% after the announcement.

"This week comes as a surprise to me," said Matt Garber, a team lead for HC Technologies in Chicago. "Last week, soybeans were supposedly shielded from being tariffed. With planting season around the corner, I hope this can be resolved soon."

On March 29, the soybeans market got a surprise in the form of the United States Department of Agriculture's Prospective Plantings report. The report showed soybean acres were projected higher than corn acres for the first time since 1983.